Dental caries-inducing microorganism cells lytic enzyme

ABSTRACT

An enzyme being capable of lysing cells of dental cariesinducing microorganisms and a method for producing the same by cultivating a microorganism belonging to the genus Streptomyces, especially wild type strains of Streptomyces diastatochromogenes, Streptomyces farinosus, Streptomyces globisporus and Streptomyces griseus var. H-402, compositions for preventing and treating dental caries containing the said enzyme and methods for preventing and treating dental caries.

United States Patent Yoshimura et al.

[ Dec. 30, 1975 DENTAL CARIES-INDUCING MICROORGANISM CELLS LYTIC ENZYME Inventors: Yoshio Yoshimura, Nishinomiya;

Kanae Yokogawa, Nara; Shigeo Kawata, Kobe, all of Japan Assignee: Dainippon Pharmaceutical Co., Ltd.,

Osaka, Japan Filed: July 11, 1972 Appl. No.: 270,821

Related US. Application Data Continuationin-part of Ser. No. 180,711, Sept. 15, 1971, abandoned, which is a continuation-in-part of Ser. No. 68,944, Sept. 2, 1970, abandoned, which is a continuation-in-part of Ser. No. 26,010, April 6, 1970, abandoned.

Foreign Application Priority Data June 7, 1969 Japan 44-45307 May 28, 1970 Japan ..44-46494 US. Cl. 195/62; 195/65; 195/68;

424/50 Int. Cl. C12D 13/10; A61K 19/00 Field of Search 195/62, 65, 66 R, 68;

1 U N IT I l. ACETATE BUFFER 2. TRlS-MALEATE BUFFER [56] References Cited UNITED STATES PATENTS 3,133,001 5/1964 Muset 195/68 3,515,642 2/1970 Mima et al...... 195/63 3,590,121 6/1971 Schiff et a1 424/50 3,682,778 8/1972 Kawai et al. 195/66 R 3,716,452 2/1973 Kitamura et al. 195/2 OTHER PUBLICATIONS Sugimoto, Agr. Biol. Chemistry Vol. 31 No. 10, pp. 1111-1123 (1967).

Primary Examiner-Lionel M. Shapiro Attorney, Agent, or FirmStevens, Davis, Miller & Mosher [57] ABSTRACT An enzy'me being capableof lysing cells of dental caries-inducing microorganisms and a method for producing the same by cultivating a microorganism belonging to the genus Streptomyces, especially wild type strains of Streptomyces diastatochromogenes, Streptomyces farinosus, Streptomyces globisporus and Streptomyces griseus var. l-1-402, compositions for preventing and treating dental caries containing the said enzyme and methods for preventing and treating dental caries.

14 Claims, 7 Drawing Figures 3. PHOSPHATE BUFFER 4. TRIS BUFFER (CONCENTRATION OF BUFFER SOLUTION: 0.02514 US, Pamm Dec.30, 1975 Sheet10f4 3,929,579

l I l J l l 4 5 e 7 a 9 l0 (pH) 1. ACETATE BUFFER 5.PHOSPHATE BUFFER 2. TRIS-MALEATE BUFFER mms BUFFER (CONCENTRATION OF BUFFER SOLUTION! 0.0m)

( UN 5 T T 4 5 6 T 8 9 (pH) l. ACETATE BUFFER 3. TRIS BUFFER 2. PHOSPHATE BUFFER CONCENTRATION OF BUFFER SOLUTION 1 0.025 N US. Patent Dec. 30, 1975 Sheet 2 of4 3,929,579

(UNIT) I20- 2 3 I00- I L l I l l I I 4 5 e 1 a 9 (pH) I. ACETATE BUFFER 5. TRIS BUFFER 2. PHOSPHATE BUFFER (CONCENTRATION OF BUFFER SOLUTION; 0.025M) FTC-L3 (UNIT) 3 so- I x I I I I I I 4 5 e 1 a 9(pH) I. ACETATE BUFFER 3. TRIS BUFFER 2. PHOSPHATE BUFFER I CONCENTRATION OF BUFFER SOLUTION; 0.025M) FIG-.4

US, atsni Dec. 30, 1975 Sheet 3 GM 3 2 7 0: l I l l I l I TEMPERATURE, C

CELL-LYTIC CURVE IN FREEZE-DRIED STREPTOCOCCUS (BHT) CELL"LYT|C CURVE IN HEAT-TREATED STREPTOCOCCUS (BHT) U ll TRIS M ALEATE BUFFER atent Dec.30,1975 Sheet40f4 3,929,579

(UNIT) REACTION TEMPERATURE C CELL-LYTIC 'CURVE IN FREEZE-DRIED STREPTOCOCCUS (BHT) CELL-LYTIC CURVE IN HEAT-TREATED STREPTOCOCCUS (BHT) FIG? DENTAL CARIES-INDUCING MICROORGANISM CELLS LYTIC ENZYME This application is a continuation-in-part of application Ser. No. 180,711, filed on Sept- 15, 1971, now abandoned, which, in turn, is a continuation-in-part of application Ser. No. 68,944, filed on Sept, 2, 1970 now abandoned, which, in turn, is acontinuation-in-part of application Ser. No. 26,010, filed on Apr; 6, 1970 now abandoned.

The present invention relates to an enzyme being capable of lysing cells of microorganisms and a method for producing the same and new compositions for preventing and treating dental caries and methods for preventing and treating dental caries.

More particularly, it relates to an enzyme being capable of lysing cells of dental caries-inducing microorganisms such as cariogenic streptococci and lactobacillus and a method for producing the same by cultivating a microorganism belonging to the genus Streptomyces, also to compositions for preventing and treating dental caries containing the said enzyme and methods for preventing and treating dental caries. 7

Since it had been pointed out by Miller in'l890 that dental caries might be induced by bacteria, causes of dental caries have been studied from a microbiological Y viewpoint by investigators. In 1960 Fitzgerald and Keyes have reported that an experimental caries was induced by streptococci in hamster (The Journal of the American Dental Association, Vol. 61', pages 9 19,"

1960). Recently, it has been reported that dental plaque or caries development could be prevented by degrading microbially produced dextran and removing away the dental plaque by using an enzyme dextranase (Fitzgerald et a1; Archives Oral Biology, Vol. 13, pages 125 128, 1968 and the Journal of the American Dental Association, Vol. 76, pages 301 304, 1968). Furthermore, it has been attempted to control the growth of dental caries-inducing bacteria by using of various compounds and medicaments and thereby to prevent or treat the dental caries. However, it has never been attempted to lyse and kill out thebacteria by using enzyme. j

There has been studied a method of preventing and treating dental caries by means of attacking in direct against the dental caries-inducing microorganisms and thereby controlling their growth. It has then found that the dental caries-inducing microorganisms such as cariogenic. streptococci and lactobacillus are a kind of microorganism being difficult to be lysed and that they could be lysed by neither egg white lysozyme which has been known as 'a' bacteria cell-lytic enzyme nor enzymes produced by type culture of several kinds of microorganisms, i.e. type culture of Streptomyces albus or Streptomyces griseus, or a strain belonging to the genus Flavobacterium which has been known as a mi- 'croorganism being able-=to produce bacteria cell-lytic enzymes.

As a result of a screening of many kinds of microorganisms existing in soil or sewage for the purpose of finding an enzyme being capable of lysing cells of den- 15 tal caries-inducing microorganisms, it"has now been found that some strains belonging to the genus Streptomyces produce an enzyme strongly lysing the said dental caries-inducing microorganisms.

One object of the present invention: is to provide an 20 enzyme being capable of lysing cells of dental cariesinducing microorganisms.

' Another object of the present invention is to provide a method for producing an enzyme capable of lysing cells of dental caries-inducing microorganisms.

A further object of the present invention is to provide compositions for preventing and treating dental caries "containing the aforesaid enzyme.

A still further object of the present invention is to provide methods for preventing and treating dental 30 caries by the application of the aforesaid compositions.

, toas EERM). They are S-l strain (ATCC-No. 21481:

PERM-P No. 326)-,-l-I-19l strain (ATCC No. 21482: FERM P No. 327 1-1-402 strain (ATCC No. 21483: FERM-P No. 328) and 13-1829 strain (ATCC No. 21553: FERMP No. 596).

The morphological, cultural and physiological characteristics of these strains are set forth in the following Table I. I

TABLE I Microscopic observation of aerial mycelium S-l strain Long straight; sporophores no spirals, no whorls; spores spherical mycelium; media 11- l 91 strain Aerial mycelium powdery white;

sporophores straight or wavy, no whorls; spores cylindrical Abundant growth light green; powdery grayish white aerial mycelium; no soluble pigment Moderate growth light green; powdery white aerial mycelium;

H-402 strain Aerial mycelium branches in cluster;

sporophores straight no spirals, no

- whorls; spores spherical Very scant thin surface growth; powdery white to yellow aerial mycelium; no soluble pigment Good growth, folding, spreading olive-buff to cream; thin,

13-1829 strain Aerial mycelium straight or wavy; no spirals, no whorls; spores spherical, 0.4

Scanty growth;

aerial mycelium light brown; 'no soluble pigment Abundant growth light ivory; powdery, creamcolored aerial Starch agar Calcium malate glycerin agar Skim-milk Potato Gelatin stab Tyrosine agar Nutrient agar Glucose nutrient agar Glucose peptone agar Litmus milk Yeast extractmalt extract agar Oatmeal agar S-1 strain turning from white to gray; soluble pigment reddish brown Abundant growth brown; cottony aerial mycelium Abundant growth reddish brown; powdery grayish white aerial mycelium; soluble pigment light reddish brown Surface ring; no aerial mycelium; coagulation; no peptonization; soluble pigment light red Abundant growth wrinkled; turning from yellow to dark brown; grayish white aerial mycelium; soluble pigment dark brown Growth on surface dark brown; no aerial mycelium; soluble pigment dark brown Abundant growth Abundant growth reddish brown; cottony gray aerial mycelium; soluble pigment reddish brown TABLE I-continued H-l9l strain no soluble pigment Moderate growth light grayish green; powdery white aerial mycelium; no soluble pigment Moderate growth light green; powdery white aerial mycelium; no soluble pigment Surface ring; no aerial mycelium; coagulation; no peptonization;

no soluble pigment Abundant growth wrinkled light brown; grayish white aerial mycelium; soluble pigment grayish w ite Growth on surface; no aerial mycelium; no soluble pigment Moderate growth dark green; powdery grayish white aerial mycelium; no soluble pigment H-402 strain powdery white cream to gray olive-buff aerial mycelium; no soluble pigment Very scanty growth, reverse yellow dull; thin, powdery gray aerial mycelium;

no soluble pigment Abundant growth, spreading light yellow; powdery white to yellow aerial mycelium; soluble pigment faint yellow Surface ring;

aerial mycelium creamy green, coagulation with rapid peptonimtion, becoming alkaline Excellent growth wrinkled turning to brown; aerial mycelium gray to olive-bufl' Faint creamcolored; rapid liquefaction;

aerial mycelium white to gray;

no soluble pigment Scanty growth, reverse yellow to light brown; aerial mycelium faint brown; no soluble pigment Abundant growth, reverse white to brown; thin, powdery aerial mycelium light gray; soluble pigment light brown B-l 829 strain mycelium; soluble pigment faint yellowish brown Moderate growth faint cocoa brown; thick, white aerial mycelium; soluble pigment faint brown Abundant growth cream-colored; powdery, creamcolored aerial mycelium; soluble pigment faint brown Thick, mossy growth wrinkled; mossy, light gray aerial mycelium; soluble pigment brown Very scanty growth; scanty, white aerial mycelium;

no soluble pigment Abundant growth faint orange; powdery, creamcolored aerial mycelium; soluble pigment faint yellow Abundant growth cream-colored; scanty, white aerial mycelium; soluble pigment faint brown Thick growth faint golden; scanty, white aerial mycelium; soluble pigment faint brown Growth with circular or thin membranous surface, light yellow; white aerial mycelium;

no soluble pigment Abundant growth bright golden; thick, creamcolored aerial mycelium; soluble pigment light brown Moderate growth faint yellowish brown; thick, white aerial mycelium;

TABLE l-continued v S-l strain H-l9l strain H-402 strain B-l829 strain soluble pigment light brown Glycerine' Abundant growth asparagine faint yellowish agar brown; thick,

powdery, creamcolored aerial mycelium; soluble pigment faint yellow b) Physiological properties I Gelatin Positive Positive Positive Positive liquefaction 2 Starch Positive Positive Positive Positive hydrolysis 3 Reduction Positive Negative Positive Positive of nitrate 4 Cellulose Negative Negative Negative decomposition 5) Tyrosinase Negative reaction 6) Litmus milk Peptonization 7) Pigment Negative producing reaction 8) Optimum C. 20 30C. 20 30C. 20 30C.

temperature 9) Optimum pH 6.5 7.5 6.5 7.5 6.5 7.5 6.5 7.5

Aerobic Aerobic Aerobic Aerobic c) Utilization of saccharide Rhamnose Xylose i i Lactose -H- i Sucrose t i Arabinose -H- -H- Rafi'inose i Fructose -H- Mannose +0- H- lnositol t Galactose +l- -H- Sorbitol Glucose -H- -H- -H- Manitol +4- Salicin Cellulose On the basis of these morphological, cultural and physiological characteristics the classification of the strains has been determined according to Bergeys Mannual of Determinative Bacteriology 7th Edition and Waksman's The Actinomycetes. Consequently, it seems that S-l st'rain, H-l9l strain and 8-1829 strain should be classified as Streptomyces diastatochromogenes, Streptomyces farinosus and Streptomyces glo-' bisporus, respectively. Furthermore, H402 strain is analogous to Streptomyces griseus but slightly distinguished from it in viewpoint of pigment production, i.e. the color in case of H-402 strain is rather yellow, orange or grayish brown than green. Therefore, it seems to be a new species. belonging to Streptomyces series and then has been designated as Streptomyces griseus var. H402.

The present enzyme can be produced by cultivation of a microorganism belonging to the genus Streptomyces, which can produce an enzyme being capable lysing cells of dental caries-inducing microorganisms, especially a wild type strain of Streptomyces diastatochromogenes, a wild type strain of Streptomyces farinosus, a wild type strain of Streptomyces globisporus or Streptomyces griseus var. H402.

The presentenzyme can be also produced by using of mutants of the described microorganisms such as those obtained by natural mutation, or those produced by mutating agent, for example, X-ray irradiation, ultraviolet irradiation, nitrogen mustards, and the like.

According to the present invention, the microorganism belonging to the genus Streptomyces is cultivated in a suitable culture medium containing, for example, proper saccharides, nitrogen sources, inorganic salts and further, if necessary, organic stimulants and thereby the desired enzyme is accumulated in the medium.

Saccharides used in the present culture may be, for example, glucose, maltose, malt extract, dextrin, starch, and the like. The nitrogen sources may be, for example, inorganic nitrogen source such as ammonium sulfate, ammonium chloride, ammonium nitrate, sodium nitrate, potassium nitrate, and the like, and organic nitrogen source such as urea, peptone, soybean extract, yeast extract, meat extract, soybean meal, and the like. Inorganic salts may be, for example, sodium chloride, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, dipotassiurn hydrogen phosphate, magnesium sulfate, ferric sulfate, zinc sulfate, calcium chloride, and the like. Furthermore, organic stimulants may be, for example, vitamins such as vitamin, B and vitamin B peptone, meat extract, corn steep liquor, and the like.

less-variedqaccording to the temperature for preser- The pH value of the medium may bepreferably-con; trolled at 6-9, more" particularly at. 78 by.'addition- Nation of' the enzyme solution, as shown in FIGS. 3 and of acids such as hydrochloric acid and"acetic"acid or; v Thejoptirnur'n'temperature is approximately 50 bases such as sodium hydroxide, potassium hydroxide 60C., as shown in FIGS. and 7. Besides, the enzyme and ammonium hydroxide. 5 of the present invention is rather unstable to heat and, The culture can be carriedout by conventional culfor example, it lost the almost activity when it was ture methods such as stationary culture, shaking culpreserved at 80C. for 20 minutes in an aqueous soluture and submerged culture,preferably by shaking tion. culture, at 20 40C., preferably at 25 37C. The The unit of lytic activity of the present enzyme and period of the culture issevejral hours to several ten 10 the reduction ratio of bacteria cells in turbidity by the days, preferably 1 to 10 days.. present enzyme were calculated according to the fol Thus obtained culture broth containing the desired lowing method. 0.4 ml. of a suspension of intact cell or enzyme can be submitted to isolation, recovery and heatedcell of microorganisms to be lysed, 2 ml. of an purification by means of conventional methodsvgenerenzyme-solution diluted in appropriate concentration ally used for the production of enzymes. Forexample, and 1.6 nil, of 0.025 M. tris buffer (pH 7.0) were mixed the culture broth may be separated by centrifuge and to to givetotal 4.0 ml. The mixture was kept at 37C. for the resulting supernatant fluid may be added water or 5 60 minutes to submit to the cell-lytic reaction. buffer solution, such as acetate buffer, phosphate Then, the optical density of the reaction mixture was buffer, tris-maleate buffer, tris buffer (tris-RC1 measured at 600 mp. of a photoelectric colorimeter and buffer), and the like to give an enzyme solution (herethe unit of lytic activity of the present enzyme and the inafter, referred to as broth enzyme solution). Furtherreduction ratio of bacteria cells in turbidity by the more, the supernatant fluid may be conventionally present enzyme were calculated according to the folpurified by means of salting out with ammonium sullowing equations. One unit of activity is defined as that fate, precipitation by acetone, dialysis and/or phosamount of enzymegivingan initial linear decrease in phoric acid gel, carboxymethyl cellulose or sephadex optical density of 0.001 per minute. As a control, 2 ml. chromatography, followed by addition of water or of water was used instead of 2 ml. of the enzyme solubuffer solution to give a purified enzyme solution tion.

(hereinafter, referred to as purified enzyme solution).

And furthermore, these enzyme solutions can be also b) (a c) cb freeze-dried to give a dried enzyme product. Both en- Umuml 0.00111 0.00ll'v zyme solutions and the dried enzyme product obtained above can P used for of composition a: Optical density of the reaction mixture at 600 my.

eprtegelntmg and treating dental caries of the present at zero reaction m n 1 FIGS. 1, 2 and 6 show the relation between pH value b: gg fi gi of he reaction mixture at 600 and microorganism cell-lytic activity of the enzyme in Optical density of the comm! solution at 600 my: case of applying the enzyme solution produced by the 1 after t time present invention to cariogenic streptococci. In FIGS. 1 R t (minute) and 6 the broth enzyme solutions were used as the Amount (ml mg) of actuauy s Original 40 enzyme solutionJn FIG. 2. thepurified enzymesolu... g m sqlutwn or powder.

' density of Optical density of theflcontrol solution the enzyme solution after the reaction aftetthereaction Opticaldensity of the control solution after the reaction tions wereusedas theenzynietsolution.FIGS. I yniedfthetpresfi tinvention can specifically how the stability-of the enzyme solution produced attack severalkinds f'de'rital caries-inducingmicroorthe present invention in which there-arecdmpared the and zshd'ws superion microorganism cell-lytic activities of the enzyme inc ase of preserving-the enactivity. ,jlh'e present, enzyme can be,jtherefore,. used zyme solutions at various pl-Lvalue for 24fhours a t'4C. for preventing and, treating l'dental caries in humans. and 37C., re spectively. FIG. 5, shows, the relation befurthermore, thepenzyrrie is also useful for preventween the temperature; andfth rel a ti;ve=activityfof the tion and treatmenti'of dental plaque which is induced by enzyme solution produced by the'present jinvention,, in dental caries-inducing microorganisms and causes of which thei'a'ctivity of the enzyme .s olutiqn reacte d vat the dental caries. "The development of the dental 37C. is used as a standard (l00).;. -FI,G.; hows the I plaque can besubsidiarily controlled as the' 'result' of relation between the temperature ,and t .activity of prevention and tteatment of'd ental carie s,bythepresthe enzyme solution producedbythe presentjnventionn cut-enzyme, Theenzyme Zus'edIin'FIGS-QI 1 05. .obtained by' The. nz inept. the present invention can be applied cultivation of H402 strain and that lGS 6 to -';I, is to, teethof ahumanfor the purpose ot' the prevention one obtained by cultivationof B-YISZQ -strain and,treatn en t.'pf.dental caries by conventional meth- The enzyme produced by theprlesent inve, loni posods conventional 'types of unipdosages or with'convensesses the activityof lysi-n g cells o f'microorganisrnsjn tional' carriers.The-conventional carriersmay be, for Wide range of pH value;;e.g.-'5 w', 9,.as sho wnin,FlGSQl, example, waten toothf powder, toothpaste, chewing 2 and6. Therange of pH value in which the present um, ointment, and the like. enzyme is stable and shows superior microorganism in the. preparation of toothpaste and tooth powder cell-lytic activity is approximately 5 9, while it is more containing the present enzyme, conventional vehicles are used unless they give essentially undesired effects to the activity of the enzyme. Suitable water insoluble polishing agent can be contained. The polishing agent may be, for example, dicalcium phosphate, tricalcium phosphate, magnesium carbonate, and the like. These polishing agents will generally comprise a major pro portion by weight of the solid ingredients. The content of the polishing agents is preferably about 30 6O by weight of the total composition in toothpaste and 85 95 by weight in tooth powder. The present enzyme is contained in the ratio of about 1 5,000 units per gram of the composition.

In the preparation of toothpaste, there may be also added some plasticizers in the mixture of the powdery vehicles to give paste. The plasticizer may be, for example, water, glycerin, sorbitol, propylene glycol, monoglycerin stearate, white petroleum jelly, cetyl alcohol, and the like, or the mixture thereof. It may be preferable to add a gelling agent such as sodium carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl pyrrolidone, gum tragacanth, and the like in the composition. Furthermore, there may be optionally added other additional components such as flavor, sweeting agent and coloring agent. According to brushing teeth with toothbrush or finger spread with these toothpaste or tooth powder containing the present enzyme, the dental caries-inducing microorganisms on the teeth can be lysed by the enzyme as well as dental plaques are eliminated and the teeth are cleaned up.

The similar effects can be achieved by using a chewing gum containing the present enzyme.

In the preparation of chewing gum containing the present enzyme, there may be used conventional gum base such as chicle resin, polyvinyl acetate, and the like. There may be also added other vehicles such as plasticizer, softener, sugar, flavor and coloring agent. The content of the enzyme may be 1 5,000 units per gram of the composition.

Other means for using the present enzyme is a form of ointment. The teeth to be treated are applied with the ointment containing the present enzyme and followed by being rubbed up by finger or a toothbrush. In the preparation of the ointment there may be used conventional vehicles being capable of applying to mouth except one having inhibitory or destructive action on the present enzyme. As an ointment base there may be used materials such as sodium carboxymethyl cellulose, hydroxyethyl cellulose and Plastibase 50 W (dental paste base made by Squibb Co., Ltd.) which can form jelly-like or creamy ointment. The content of the present enzyme may be I 3,000 units per gram.

The present enzyme may be also applied to teeth by means of making a person wash or rinse his mouth with a water containing the enzyme. The water contains about 0.1 50 units per milliliter of the present enzyme. It may further contain antibiotics or other sterilizers, and alcohols, flavor, sweetening agent and coloring agent. The washing with the water containing the present enzyme may be also carried out by using a spray.

For mouth wash there may be also used an effervescent granule. In the preparation of the effervescent granule tartaric acid and sodium hydrogen carbonate are used as an effervescent agent and thereto the present enzyme is added in a dose of l 5,000 units per gram of the granule. There may be optionally added other vehicles such as flavor, sweetening agent and coloring agent. The effervescent granule is added to 10 water in a ratio of one gram per 200 to 300 ml. of water when used, and thereby it can be instantaneously dissolved with effervescing. The solution thus obtained is used as a mouth wash.

In these cases, after washing or rinsing the mouth, it maybe preferable not to rinse the mouth with clean water since it is desirable to make the enzyme contact with teeth for a long period.

The present enzymemay be also used in a form of chewable tablet or troche. According to chewing or keeping the chewable tablet or troche containing the present enzyme in a mouth the enzyme can be sufficiently in contact with teeth for a long period. In preparation of the chewable tablet or troche containing the present enzyme there may be used conventional vehicles such as mannitol and sorbitol, and other conventional lubricant, sweetening agent, coloring agent, etc. The content of the enzyme may be I 5,000 units in a dose unit.

The present enzyme may be admixed with confectionery such as candy, cake, and the like.

Furthermore, the present enzyme may be administered in admixture with food stuffs or beverage In this case the enzyme may be mixed with food stuffs or beverage before or after processing thereof.

The method for application of the present enzyme for the purpose of prevention and treatment of dental caries is not limited to the above described methods and many other variants or modifications can be employed. However, in the preparation of the compositions containing the present enzyme it should be noted that heat treatment should be avoided since the present enzyme is unstable to heat and therefore, if necessary, the enzyme should be admixed after the heat treatment.

The present enzyme is unstable to heat as mentioned above and furthermore when the enzyme a or composition thereof is preserved at a room temperature for a long period, the enzyme will be gradually deactivated. Thus, the present enzyme is very unstable and therefore the activity of the enzyme will be lowered in the purification step of raw enzyme obtained by cultivation of the present microorganisms or in the preparation step or the preservation of the compositions containing the enzyme to result in the low yield or the lowering of quality of the product. In view of these disadvantages, it has been studied to find out a stabilizer suitable for stabilizing the present enzyme and then it has been found out that some stabilizers are useful for the purport. Examples of most suitable stabilizer are sucrose, mannose, sorbitol, proline, sorbose, soluble starch and carboxymethyl cellulose and its sodium salt. Among these stabilizers, soluble starch does not show stabilizing effect in aqueous state but is effective in solid state and therefore it can not be used in aqueous compositions but only in solid state compositions. Besides, various grades of carboxymethyl cellulose may be used but it is preferable to be water soluble, especially to be in the form of sodium salt.

To the present enzyme or the enzyme-containing solution obtained by cultivating a microorganisms belonging to the genus Streptomyces are added one or more stabilizers above-mentioned to give a stable enzyme solution or powder.

If necessary, especially in case of using soluble starch as the stabilizer, the solution is freeze-dried to give a stable enzyme powder. Thus obtained stable enzyme solution or powder may be used as mouth wash or rinse after being diluted with or dissolving in water, and

1 1 further it may be admixed with a carrier to give a stable composition. The stabilizer may be also added in the course of the preparation of enzyme-containing compositions.

These stabilizers may be added alone or in a mixture of two or more kinds of the stabilizers to solution or compositions containing the enzyme in a ratio of about 0.5 part to about 100 parts by weight more preferably about 1 part to about 30 parts by weight in case of sucrose, mannose, sorbitol, proline and sorbose, about 0.5 part to about 80 parts by weight, more preferably about parts to about parts by weight in case of soluble starch and about 0.3 part to about 5 parts by weight, more preferably about 0.7 part to about 2 parts by weight in case of carboxymethyl cellulose or its sodium salt to 1 part by weight of the enzyme.

The quantity of the present enzyme used for the.

preparation of the present compositions may be variable in accordance with kinds of the compositions and the methods for application as described above, but may be admixed so as to be used 1 5,000 units, more preferably 10 3,000 units of the enzyme at one time.

The enzyme of the present invention does not show any toxicity or any undesirable side effect even though it would be used for a long time. If the present enzyme would be swallowed, it is deactivated or decomposed in the stomach and converts to harmless amino acids. By contrast, most antibiotics which are generally used for inhibiting various kinds of microorganisms possess wrong effects on intestinal microflora.

The present enzyme has further benefit that there has no enzyme resistant strain of dental caries-inducing microorganisms, while the microorganisms are resistant against most antibiotics.

According to the application of the present enzyme not only cells of the dental caries-inducing microorganisms are lysed and thereby the dental caries is prevented and treated but also the teeth themselves can be made whitethough the reasons are not elucidated.

The present enzyme can lyse not only dental cariesinducing microorganism cells but also cells of other several kinds of microorganisms, especially gram positive bacteria, particularly those belonging to the genus Bacillus and. Lactobacillus.

The preparation of the present enzyme and the compositions containing the enzyme are set out in the following Examples which are illustrative but not limiting. Unless otherwise noted, the percentages in the compositions of the medium are by weight per volume.

EXAMPLE 1 The isolated l-l-l9l strain was inoculated on a slant agar medium containing 1 of glucose, 0.2 of peptone, 0.1 of yeast extract, 0.1 of meat extract and 1.5 of agar and cultivated at 30C. for 7 days. To the agar slant culture was added 5 ml. of sterilized water and thereby the spores were washed out to give a suspension of spore. 0.5 ml. of thus obtained suspension was inoculated into a 200 ml. Roux flask including 50 ml. of liquid medium (pl-l 7.5) containing 0.5 of glucose, 0.5 of peptone, 0.5 of sodium chloride, 0.2 of dipotassium hydrogen phosphate, 0.1 of magnesium sulfate, 0.004 of calcium chloride, 0.002 of ferric sulfate and 0.01 of zinc sulfate and submitted to stationary culture at 30C. for 7 days. The obtained culture broth was separated by centrifuge and the resulting supernatant fluid was diluted with distilled 12 water to give an enzyme solution of ten times by volume on which the unit was calculated.

Separately, several kinds of cariogenic streptococcus to be lysed, each 3 -4 platinum loops were inoculated into a 200 ml. flask including 190 ml. of liquid medium (pH 7.4) containing 2 of glucose, 1 of peptone, l of meat extract, 0.5 of sodium chloride, 0.2 of yeast extract, 1 of sodium acetate and l X 10 M. manganese sulfate and submitted to stationary culture at 37C. for 2 days. The produced cells were harvested by centrifuge and washed with water twice. The harvested cells were dispersed into 10 ml. of distilled water and sterilized by heating at 100C. for 20 minutes. The sterilized dispersion was used as a sample to be tested.

To 0.4 ml. of the sample to be tested were added 2 ml. of the enzyme solution obtained above and 1.6 ml. of 0.025 M. acetate buffer (pH 6.0) to give total 4 ml. The mixture was reacted at 37C. for several 10 minutes. The optical density of the reaction mixture at 600 mp. of a photoelectric colorimeter was measured and then the reduction ratio of the microorganisms to be lysed was calculated in accordance with the equation described above. The results are as shown in Table I].

The isolated l-l-402 strain was cultivated in the same manner as described in Example 1 to obtain an enzyme solution. On the other hand, intact cell of cariogenic streptococcus (Bl-1T) was cultivated in the same manner as described in Example 1 to obtain a sample to be tested.

By using these enzyme solution and sample to be tested, the cell-lytic reaction was carried out in the same manner as described in Example 1 and the reduction ratio of the microorganisms to be lysed was calculated as well. The results are shown in Table 111.

The isolated 11-402 strain was cultivated in the same manner as described in Example 1 and the obtained culture broth was separated by centrifuge. The resulting supernatant fluid was used as the broth enzyme solution. Besides, the supernatant fluid was further salted out by saturating with ammonium sulfate so as to be 60 saturation. The resulting precipitate was dissolved in 0.05 M. phosphate buffer (pH 7.5) and subjected to dialysis. To the solution was added acetone so as to be 40 acetone. After removing the resultant precipitate, acetone was further added to the supernatant fluid so as to be 60 acetone. The resultant precipitate was dissolved in the buffer solution above-mentioned and subjected to dialysis. To the resulting supernatant fluid was added 10 aqueous calcium chloride solution and the precipitate was removed. The supernatant fluid was used as the purified enzyme solution.

Separately, cariogenic streptococcus (Bl-1T) was cultivated in the same manner as described in Example 1. The obtained cells were freeze-dried and dispersed in distilled water to give a sample to be tested.

To 0.4 ml of the sample to be tested were added 1.6 ml of 0.025 M. acetate buffer (pH 6.0) and 2 ml of the broth enzyme solution diluted to ten times by volume with distilled water or 2 ml. of the purified enzyme solution diluted to 500 times by volume with distilled water to give total 4.0 ml. The mixture was reacted at 37C. for 30 minutes. The optical density of the reaction mixture at 600 mp. was measured and then the unit of the enzyme and the reduction ratio of the microor' ganisms to be lysed were calculated in accordance with the equation above-mentioned. The results are shown in Table IV.

The isolated 11-402 strain ws cultivated in the same manner as described in Example 1. By using the obtained enzyme solution, cell-lytic reaction was caried out on several kinds of microorganisms in the same manner as described in Example 1 and the unit was calculated. The results are shown in Table V.

TABLE V Microorganisms to be lysed Unit/ml.

(l Gram positive bacteria Cariogenic streptococcus (Bl-1T) 95 Streptococcus salivarius 90.7 Streptococcus lactis 13.3 Streptococcus bovis 17.1 Streptococcus faecalis 105.5 Micrococcus lysodeikticus 16.2 Sarcina lutea 12.9 Staphylococcus albus 34.2 Staphylococcus aureus 25.7 Bacillus subtilis PCl 219 153.9 Bacillus sphaericus 199.5 Bacillus megaterium 28.0 Tetracoccus soyae 12.9 Lactobacillus acidophilus 36.8 Lactobacillus arabinosus 73.6 Lactobacillus bulgaricus 25.9 Lactobacillus casei 8.6 Lactobacillus hiochi [F 3077 20.1 Lactobacillus hiochi lFO 3078 31.6 Lactobacillus hiochi lFO 3079 20.1

(2) Gram negative bacteria Escherichia coli 3.8 Aeromonas hydrophila 5.7 Arthrobacter simplex 6.7 Proteus OM-9 2.2 Cellulomonas flavigena 13.3 Flavobacterium esteroaromaticum 16.7 Pseudomonas fluorescens 17.1 Pseudomonas aeruginosa 14.7

EXAMPLE The isolated H-402 strain was cultivated in the same manner as described in: Example 1 and the obtained culture broth was separated by centrifuge. The resulting supernatant fluid was salted out by 60 saturation with ammonium sulfate. The resulting precipitate was dissolved in 0.05 M. phosphate buffer (pH 7.5) and subjected to dialysis. To the solution was added acetone so as to be 40 acetone. After removing the resultant precipitate, acetone was further added to the supernatant fluid so as to be 60 acetone. The resultant precipitate was dissolved in the buffer solution above-mentioned and subjected to dialysis. To the resulting supernatant fluid was added 10 aqueous calcium chloride solution and the precipitate was removed. The supernatant fluid was freeze-dried to give an enzyme sample which activity was 544 units/mg. The enzyme sample was used in the following experiment.

Golden hamsters fed cariogenic diet (Krasse: Archives Oral Biology, Vol. 10, page 215, 1965 being 21 days old, were used in the experiment. After confirming no existence of streptomycin-resistant bacteria in the mouth, a streptomycin-resistant strain of cariogenic streptococcus (K-l-R) was introduced into cheek pouches of the hamsters. To one group of the hamsters was administered drinking water containing 7.5 units/ml. of the enzyme. About 10 ml. of the drinking water was drunk every day. To other group of the hamsters was administered drinking water containing no enzyme. About 10 ml. of the drinking water was drunk every day. Samples of dental plaques were collected by means of swab on some days after the infection.

The samples were dispersed into yeast extract solution and diluted optionally with distilled water. The solution was inoculated in Mitis salivarius agar medium containing streptomycin and cultivated at 37C. for 40 hours, and then the formed colonies were counted. The results are shown in Tables VI and VII. In the Tables results of samples after 7 and 11 days are given, respectively.

TABLE VI Numbers of colonies (X 10?) Control Added enzyme (No added enzyme) TABLE V" Numbers of colonies (X 10) Control Added enzyme (No added enzyme) w-coo EXAMPLE 6 The isolated B-1 829 strain was inoculated on a slant agar medium containing 1 of glucose, 0.2 of pepcontaining 2 of dext'rin, 0.5 ofsoybeari powder,

0.25 of peptone, 0.5 of disodiu'iij hydrogen phos;

phate, 0.1 of potassium dihydrogen phosphate, l. of magnesium sulfate and 0.5 ofsodium chloridefand subjected to shaking culture at 30C,. for3days. The obtained culture broth was separated byfiltrationand the resulting filtrate was diluted with distilled. water to give an enzyme solution of times by'volume on which the unitwas calculated.

Separately, several kinds of cariogenic streptococcus to be lysed, each 3 4 platinum loops were inoculated into a 200 ml. flask including 190 ml. of liquid medium (pH 7.4) containing 2 of glucose, 1 of pepto'nejl' of meat extract, 0.5 of sodium chloride, 0.2 of yeast extract, 1 of sodium acetate and l X lO M. manganese sulfate and subjected to stationary culture at 37C. for 2 days. The produced cells were harvested by centrifuge, washed withwater twice, centrifuged and freeze-dried. 1

To 0.4 ml. of a solution which was prepared by dissolving 100 mg. of the freeze-dried cells obtained above into ml. of distilled water were added 2 ml. of the enzyme solution obtained above and 1.6' mllof 0.025 M. tris buffer (pl-l 7.0)to give total 4 ml. The mixture was reacted at 37C. for 5 minutes. The optical density of the reaction mixture at 600 my, of a photoen lectric colorimeter was measured andthen the reduc tion ratio of the microorganisms to be lysed was calculated in accordance with the equation describedv above. The results are shown in Table Vlll.

The isolated 8-1829 strain was cultivated in thesame manner as described in Example 6 to obtain anenzyme solution. On the other hand, intact cells ofcariogenic streptococcus (BHT) were cultivated the same manner as described in Example 6 to obtain freeze-dried cells which dissolved into distilled water to give a sample to be tested.

By using these enzyme solution and sample to be tested, the cell-lytic reaction was carried out in the same manner as described in Example 6 and the reduction ratio'of the microorganisms to belysed was calculated as well. The results are shown'in'Ta'ble'lX.

y "TABLE Ix yolurne of enzyme solution Reduction ratio added into 4 ml. of the reaction mixture (ml) 5 minutes 10 minutes EXAMPLE 8 The isolated 8-1829 strain was cultivated in the same manner as described in Example 6. By using the obtainedenzyme solution, the cell-lytic reaction was carried-on the various microorganisms in the same manner as described in Example 6 and the unit was calculated. The results are shown in TableX.

TABLE X Microorganisms to be lysed Unit/ml.

( l) Gram positive bacteria Cariogenie streptococcus (BHT) 455 "Streptococcus salivarius 272 Streptococcus lactis 66 Streptococcus bovis 456 Streptococcus faecalis Micrococcus lysodeikticus 30 Sarcina lutea 24 Sarcina marcescens 4 Staphylococcus albus 218 Staphylococcus aureus 18 30 Bacillus subtilis 1040 Bacillus sphericus 784 Brevibacterium ammoniagenes Lactobacillus acidophilus 36 Lactobacillus arabinosus 116 Lactobacillus brevis 500 Lactobacillus bulgarieus- 236 Lactobacillus casei 60 Leuconostoc mesenteroides 434 Tetracoccus soyae 90 (2) Gram negative bacteria Aerobacter aerogenes 658 Aeromonas hydrophilia 86 Acromobacter liquidum 40 Alcaligenes-faecalis 68 Cellulomonas flavigena 706 Escherichia coli' 40 Flavobacterium esteroaromaticum 168 Pseudomonas fragi I v 208 Pseudomonas aeruginosa 56 Pseudomonas fluorescens 56 (3) Other microorganisms =Mycobaeterium phlei 224 .Candida albicans 32 Saccharomyces cerevisiae 60 Candida utilis I6 EXAMPLE 9 The spores of the isolateed B-1829 strain obtained in the same manner as described in Example 6 were inoculated into three 500 ml. Sakaguchi flasks including 50 ml. of liquid medium having the same composition as described in Example 6 and subjected to shaking culture at 30C. for 24 hours.

17 min., an agitation velocity of 150 r.p.m. The unit of the obtained enzyme at each culture period are shown in Table Xl.

After 10 liters of the culture broth obtained by the same manner as described in Example 6 was separated by filtration, the filtrate was added onto 400 g. of cationic exchange resin Amberlite CG 50. The mixture was adjusted at pH 5.2 5.5 with concentrated aqueous ammonia, agitated under cooling for one hour and filtered. The adsorbed enzyme on the resin was eluted with its volume of 0.2 M. disodium hydrogen phosphate aqueous solution (pH 7.5). The eluate was salted out by 60 saturation with ammonium sulfate (455 g. of ammonium sulfate per liter of eluate). The resulting precipitate was dissolved into 200 ml. of 0.05 M. phosphate buffer (pH 7.0) and dialyzed against 3 liters of the same buffer in cellophane tube for 24 hours to obtain 200 ml. of solution. To thus obtained solution was added 1 10 volume of diethylaminoethyl cellulose, and then the mixture was filtered and freeze-dried to give 2.5 g. of enzyme powder which activity was 400,000 units/g.

EXAMPLE 1 1 A toothpaste having the following prescription was prepared.

EXAMPLE 13 A dental liquid having the following prescription was prepared.

Potassium lauryl sulfate 0.3 Ethyl alcohol 8.0 Saccharin 3 Flavor l 0 The enzyme solution obtained by Example 6, not diluted Distilled water balance EXAMPLE 14 A chewable tablet having the following prescription was prepared.

The enzyme solution obtained by Example 6, not diluted 0.3 Corn starch 10 Talc 2 Saccharin 0.5 Flavor 0.2 Sorbitol balance EXAMPLE l5 TABLE Xll Stabilizer Remaining activity Kind Concentration of enzyme by weight) Control Sorbitol 50 89.4 Sorbitol 94.8 Mannose 70 82.0

Sucrose 70 82.7 Proline 30 69.4 Proline 40 73.4 Proline 50 88.3 Sorbose 60 68.5

Polyethylene glycol 30 12.8 Polyoxyethylene sorbitan mono- 0.01 14.7

oleate (Tween Sorbitan monooleate 0.01 l l .5

(Span 80) Maltose 50 12.5 Glucose 70 35.7 Glycerine 20 17.1 Mannitol 10 25.7 Soluble starch 10 24.6 Lactose 10 21.6 Xylose 70 13.3 lnositol 10 25.0 Glycine 0.5 19.0 Cysteine HCl 0.5 15.3 Sodium glutamate 1 26.7

starch is not effective in aqueous solution but effective in solid state com-positions).

EXAMPLE 16 Into 150 ml. of a 70 by weight aqueous solution of sorbitol was dissolved 150 mg. of enzyme powder obtained by Example 10 and the mixture was allowed to stand at 30C. for 1 month. The change of the remaining activity of enzyme was observed. The results are shown in Table XIII.

TABLE XIII Remaining activity of enzyme Days Control Sorbitol added 100.0 100.0 7th 22.5 99.6 14th 11.1 88.1 21th 7.8 76.7 30th 7.2 71.6

EXAMPLE 17 In the same manner as described in Example 16, except that a 50 by weight aqueous solution of proline was used instead of a 70 by weight aqueous solution of sorbitol, there was tested the stabilizing effect of proline. The results are shown in Table XIV.

TABLE XIV R D activity of enzyme Days Control Proline added 0 100.0 100.0 7th 23.4 100.0 14th 1 3.2 94. 1 2 1 th 8.5 82.2 30th 7.8 76.9

EXAMPLE 1 8 Into 1 ml. of water was dissolved 15 mg. of enzyme powder obtained by Example 10 and further 20 mg. of

sorbitol. The mixture was freeze-dried. After the product was allowed to stand at 30C. for 3 months, the activity of enzyme was measured and then a lowering of the activity of enzyme was little found.

EXAMPLE l9 Into 1 ml. of water was dissolved mg. of enzyme powder obtained by Example 10 and further mg. of sucrose. The mixture was freeze-dried. After the product was allowed to stand at 30C. for 3 months and the activity of enzyme was measured. The lowering of the activity of enzyme in the product was less than 10 EXAMPLE 20 A freeze-dried product of 2 ml. of the enzyme solution obtained by Example 6, not diluted with water, 10 g. of sorbitol powder, 360 g. of disodium hydrogen phosphate (Na HPO .l2I-I O), 140 g. of potassium dihydrogen phosphate (KH,PO.,), 1 g. of saccharin and 0.5 g. of flavor were mixed to give a powdery mixture. The mixture may be diluted to 200 times with distilled water before the use and then applied into mouth.

EXAMPLES 21 25 Aqueous solutions of soluble starch having various concentration were prepared by dissolving soluble starch into water on heating and then cooling the mixture. Into 5 ml. of each of the aqueous solutions pre- 20 pared above were dissolved 60mg. of enzyme powder. The mixtures were freeze-dried to give powders. Thus obtained powders were allowed to stand at 40C. for 9 days and then the remaining activity of enzyme'was measured. The results are shown in Table The powder obtained in the same manner as described in Example 21 and Control powder were allowed to stand at 30C. for 6 months. And then the remaining activity of enzyme was measured. Although in Control powder the activity was lowered to 3.8 in the powder containing soluble starch almost of activity was remained.

EXAMPLE 27 To 2 ml. of water was added mg. of soluble starch and the mixture was heated to dissolve the starch and then cooled. Into the aqueous starch solution were dissolved 20 mg. of freeze-dried enzyme obtained by Example 10 and the mixture was freeze-dried to give mg. of a stabilized enzyme powder.

After being dissolved into 100 ml. of water, the pow- I der obtained above can be used as a mouth wash.

EXAMPLE 28 In 1 ml. of each aqueous solution (concentration: 0, 0.5, 1.0 and 3.0 by weigh) of sodium carboxymethyl cellulose (Celogen FSB (viscosity: 340 cps.) made by Daiichi Kogyo Seiyaku K.I(.) was dissolved 15 mg. of the enzyme powder obtained by Example 10 and the mixture was freeze-dried to give a sodium carboxymethyl cellulose-enzyme powder. The powder was allowed to stand at 80C. for 4 days and then measured the remaining activity of the enzyme. The results are shown in Table XVI.

Table XVI Concentration of aqueous Remaining sodium carboxymethyl activity cellulose solution of the enzyme' Activity of original powder before allowed to stand at 80C. 100

EXAMPLE 29 To 1 g. of paste base consisting of 5.0 parts by weight of Plastibase 50 W, 0.83 part by weight of gelatine and 0.415 part of pectine was added the sodium carboxymethyl cellulose-enzyme powder obtained in the same manner as described in Example 2850 as to be 10 mg. of enzyme and the mixture was kneaded well to give a 21 paste containing the enzyme. The paste was allowed to stand at 80C. for 4 days and then calculated the remaining activity of the enzyme. The results are-shown in Table XVII.

Table xvn Period for Concentration of aqueous sodium allowing carboxymethyl cellulose solution to stand (hour) 0.5 1.0 3.0

EXAMPLE 30 Table XVIII Sodium carboxymethyl cellulose Remaining activity Kind Concentration of the enzyme Terucello H 0.5 117.4 1.0 108.4 2.0 102.9

Terucello M 0.5 95.6 1.0 96.0 2.0 95.5

EXAMPLE 31 Plastibase 50 W Hydroxyethyl cellulose Sodium carboxymethyl cellulose-enzyme powder a-Soluble starch Ma nesium sulfate S ium saccharin Coloring agent Flavor 0:7 slight amount slight amount The paste thus obtained was very stable, and even when it was preserved at a room temperature for twelve months, the activity of the enzyme did not lower.

EXAMPLE 32 I Inthe same manner as described in Example 28, a sodium carboxymethyl cellulose-enzyme powder was obtained by usingl ml. of 3 aqueous'solution of sodium carboxymethyl cellulose (Celogen FSB made by'Daiichi Kogyo Seiyaku K.I(.) and mg. of the enzyme powder obtained in. the same manner as in Example 10. By usingthe sodium carboxymethyl cellulose-enzyme powder, a troche having the following prescription was prepared.

e) Mannitol 278.2 Sodium carboxymethyl cellulose 10.0 Sodium carboxymethyl cellulose-enzyme powder I 3.0 Magnesium sulfate 5.0 Magnesium stearate 1.5 Sodium saccharin 0.3 Flavor slight amount The troche thus obtained was very stable, and when it was preserved at a room temperature for 12 months,

the activity of the enzyme did not lower.

EXAMPLE 33 By using a sodium carboxymethyl celluloseenzyme powder obtained in the same manner as described in Example 31, an effervescent granule having the following prescription was prepared.

e) Tartaric acid Sodium hydrogen carbonate 188 Magnesium sulfate 12 Mannitol 412 Lactose 250 Sodium saccharin 5 Levo-menthol 5 Sodium carboxymethyl cellulose-enzyme powder 3.7

When the effervescent granule thus obtained was preserved at a room temperature for 12 months, the activity of the enzyme did not lower. The granule is dissolved in about 200 ml. of water when used and then it is used as a mouth wash.

What is claimed is:

1. An enzyme capable of lysing cells of cariogenic streptococci produced by cultivation of a Streptomyces microorganism selected from the group consisting of Streptomyces diastatochromogenes (ATCC 21481), Streptomyces farinosus (ATCC 21482), Streptomyces globisporus (ATCC 21553) and Streptomyces griseus Var. H-402 (ATCC 21483) and mutants thereof.

2. The enzyme according to claim 1, wherein said microorganism is Streptomyces diastatochromogenes or mutant thereof.

3. The enzyme according to claim 1, wherein said microorganism is Streptomyces farinosus or mutant thereof.

4. The enzyme according to claim 1, wherein said microorganism is Streptomyces globisporus or mutant thereof.

5. The enzyme according to claim 1, wherein said microorganism is Streptomyces griseus var. H402 or mutant thereof.

6. A method ofproducing an enzyme capable of lysing cells of dental caries-inducing microorganisms which comprises cultivating a Streptomyces. microorganism selected 7. The method according to claim 6, wherein said microorganism is Streptomyces diastatochrorno genes or mutant thereof.

8. The method according to claim 6, wherein said microorganism is Streptomyces farinosus" or'mutant.

thereof.

9. The method according to claim 6, wherein said microorganism is Streptomyces globisporus or mutant thereof.

10. The method according to claim 6, wherein said microorganismjs Streptomyces griseus var. H-402 or mutant thereof.

. .11. T he method according to claim 6, wherein said cultivation is carried out at 20 to 40C. for several hours to several ten days.

12. A-method for stabilizing an enzyme in accordance with claim 1 which comprises adding at least one of stabilizer selected from the group consisting of sorbitol, sucrose, mannose, sorbose,-proline, soluble starch to the enzyme or the enzyme-containing composition.

' 13; A stable enzyme solution or powder comprising an enzyme in accordance with claim 1 and at least one of stabilizer selected from the group consisting of sorbi tol, sucrose, mannose, sorbose, and proline.

l4. A stable enzyme powder comprising an enzyme in accordance with claim 1 and soluble starch as a stabilizer. g i 

1. AN ENZYME CAPABLE OF LYSING CELLS OF CARIOGENIC STREPTOCOCCI PRODUCED BY CULTIVATION OF A STREPTOMYCES MICROORGANIISM SELECTED FROM THE GROUP CONSISTING OF STREPTOMYCES IDASTATOCHROMOGENES (ATCC 21487), STREPTOMYCES FARINOSUS (ATCC 21482), STREPTOMYCES GLOBISPORUS (ATCC 21553)
 2. The enzyme according to claim 1, wherein said microorganism is Streptomyces diastatochromogenes or mutant thereof.
 3. The enzyme according to claim 1, wherein said microorganism is Streptomyces farinosus or mutant thereof.
 4. The enzyme according tO claim 1, wherein said microorganism is Streptomyces globisporus or mutant thereof.
 5. The enzyme according to claim 1, wherein said microorganism is Streptomyces griseus var. H-402 or mutant thereof.
 6. A method of producing an enzyme capable of lysing cells of dental caries-inducing microorganisms which comprises cultivating a Streptomyces microorganism selected from the group consisting of Streptomyces diastatochromogenes (ATCC 21481), Streptomyces farinosus (ATCC 21482), Streptomyces globisporus (ATCC 21553) and Streptomyces griseus Var. H-402 (ATCC 21483) and mutants thereof; and recovering the produced enzyme from the culture broth.
 7. The method according to claim 6, wherein said microorganism is Streptomyces diastatochromogenes or mutant thereof.
 8. The method according to claim 6, wherein said microorganism is Streptomyces farinosus or mutant thereof.
 9. The method according to claim 6, wherein said microorganism is Streptomyces globisporus or mutant thereof.
 10. The method according to claim 6, wherein said microorganism is Streptomyces griseus var. H-402 or mutant thereof.
 11. The method according to claim 6, wherein said cultivation is carried out at 20* to 40*C. for several hours to several ten days.
 12. A method for stabilizing an enzyme in accordance with claim 1 which comprises adding at least one of stabilizer selected from the group consisting of sorbitol, sucrose, mannose, sorbose, proline, soluble starch to the enzyme or the enzyme-containing composition.
 13. A stable enzyme solution or powder comprising an enzyme in accordance with claim 1 and at least one of stabilizer selected from the group consisting of sorbitol, sucrose, mannose, sorbose, and proline.
 14. A stable enzyme powder comprising an enzyme in accordance with claim 1 and soluble starch as a stabilizer. 